Developers of distributed information systems are faced with daunting complexities. The traditional approach to system design and development requires a monumental task of understanding constantly changing requirements, while designing and implementing the system as a whole. The requirements for the system are collected and interpreted by software developers who are not the domain experts. At the same time, people who have an intimate knowledge of the system requirements are not the software engineers.
There are several inherent problems with existing approaches:
1. Multi-phased design and development process that is not extensible.
Difficulty in communication between developers and domain experts results in multiple iterations of a system design and multiple patches and changes to the delivered product. Such a system, when completed, becomes a legacy island in the enterprise that is impossible to change, extend, or integrate into the global information infrastructure.
Prior art solutions have tried to solve this major problem by introducing new languages targeted to capture requirements for the system design, such as the graphical “Use Cases” language of UML. These new languages add an extra level of complexity and require a high level of commitment from both groups involved in the design and development process. The biggest problem with this approach is that the design model is not present in the system delivered to the customer. An end user gets a system that consists of files, modules, and executables, but not of accounts, machines, units, etc. From the end users' standpoint, all of the time that went into the requirements capturing and modeling was wasted, because the system does not represent their real-world entities that they interact with, but some foreign entities forced on them by the system implementation.
This prior art approach does not help developers simplify the design and implementation of the system. Developers have to deal with the details of a target deployed environment, communication and hardware. An object-orientated approach to the system implementation, while helping in the design process, leaves them with monolithic applications once compiled.
2. Changes are difficult to make.
This application orientation makes prior art approaches much more difficult to use in the environments where requirements are constantly changing and system complexities are increasing. Even component specifications that have been introduced did not address the distributed nature of the systems, nor did they help to solve the complexities of the development process, and were a mere extension of the client-server model of the past.
3. Communication between applications is limited.
Monolithic applications have no way to interact with other applications deployed in the enterprise. A special integration infrastructure has to be used to build an integration layer to pull it all together. This integration is an afterthought solution that is an application by itself and has all the problems noted above.
4. Difficulty in transferring large amounts of data to a central point.
With traditionally developed information systems, decision-making is centralized even though the information sources are distributed throughout the enterprise. Generally, information is transferred to a central point where it is processed. In physically distributed enterprises, with either large buildings or worldwide operations, it is very difficult to transfer large amounts of information to a central point. Often the solution is to install multiple copies of an application, each in an area of the enterprise. This results in unconnected islands, with little or no synchronization between areas.
5. Not designed for real-time.
Most prior art applications were not designed for real-time behavior. With the exception of real-time control systems, most applications were designed to run periodically, perhaps a few times a day or once a week to update inventory, send orders to the suppliers, or process production data for the last day or week. This limitation prevents businesses from immediately reacting to the needs of customers or reacting to problems with internal operations. There is a need to have all applications, including supply chain management, e-commerce and plant-floor operations, to react in real-time as an integrated enterprise.